1. Field of the invention
The present invention relates to a touch screen using infrared cameras and, more particularly, to a touch screen using infrared cameras hardly affected by external disturbance light, which includes an infrared radiation base having a plurality of infrared emitting elements and the infrared cameras, thereby preventing malfunction resulting from the external disturbance light.
2. Description of the Related Art
In general, a touch screen serves as an interface between a telecommunication apparatus using a display and a user. Particularly, the touch screen is an input device that can interface the user with such an apparatus by allowing the user to directly touch a screen part with a finger or a stylus.
This touch screen is the input device capable of allowing men and women of all ages to easily use the touch screen by touching a button displayed on the screen with a finger in order to manipulate a computer in an interactive and intuitive manner. As such, the touch screen is presently applied to various fields such as personal digital assistants (PDAs), liquid crystal displays (LCDs), cathode ray tubes (CRTs), banks, government and public offices, various kinds of medical equipment, tourism and main organization information services, traffic information services, and so on.
As for one of the representative techniques realizing the touch screen, a resistive film technique is configured so that a thin metal sheet is attached to X- and Y-axial sides on which chemicals are applied between a glass panel and a thin film. When this type of panel is powered on, a predetermined quantity of resistance is generated in the panel. Then, when a finger or the other object touches a portion of the panel, the chemicals respond to such a touch, and thus the resistance is abruptly varied. In the metal sheet, a positional coordinate, at which the object is touched, is detected from the variation of the resistance.
However, in the case of this resistive film technique of the conventional touch screen, it is difficult to apply the resistive film technique to a large screen, and the resistive film is easily damaged. Thus, it is impossible to apply the resistive film technique to a screen having a portion that is frequently touched by the user or the other object.
Further, another technique realizing the touch screen is configured to recognize a coordinate on the screen using visible light or infrared light. Among them, the touch screen using the infrared light arranges infrared transceiving elements throughout an outer circumference thereof, so that the number of the infrared transceiving elements is increased, and the production costs are increased. Particularly, in the case in which the touch screen is greatly influenced by an external environment, for instance, by sudden exposure to strong light, the touch screen is directly influenced by external disturbance light, so that an infrared receiving part of the infrared receiving element abnormally represents peak detection value. Thus, although no touch is performed by the user, a detection value of the infrared receiving part is recognized to be remarkably low compared to the abnormally increasing peak detection value, so that the touch screen recognizes that the object exists. Consequently, the touch screen is very vulnerable to the external disturbance light.